MANCHESTER, ENGLAND - JUNE 05: Darth Vader attends adidas Host The Street Party at Coronation Street, ITV studios on June 5, 2010 in Manchester, England. (Photo by Shirlaine Forrest/Getty Images for adidas)
TV - Movies
The Canonical
Reason Darth
Vader Can't Use
Force Lightning
Makes Sense
Ever since “A New Hope” first hit theaters in 1977, Darth Vader has become one of the most iconic movie villains of all time. Within the “Star Wars” universe, he’s one of the most powerful and terrifying Sith to ever roam the galaxy, yet, confusingly, there is one aspect of the force which Vader seems completely unable to use: Force lightning.
Outside of the films, there's actually a canonical reason why he is unable to wield Force lightning. Marvel's canonical comic "Darth Vader" #8, reveals his entire torso is a roiling mix of blood-red energy, but his robotic limbs appear as white outlines with nothing in them at all.
Although we know Vader can certainly wield the Force through his robotic limbs, the comic makes it clear that the Force does not reside in his limbs, and as such it's likely that Vader is unable to channel Force lightning through them. Furthermore, short exposure to the lightning of Emperor Palpatine melted metal, so it stands to reason that Vader, mostly made of metal, could melt trying to use it.
To be fair, Vader actually does wield Force lightning in Marvel's "Darth Vader" #25, but explicitly does so without his hands — controlling it remotely outside of his own body. In any case, it's made abundantly clear that Vader's limitations are not a question of power, but a result of the damage he endured in that fateful battle on Mustafar.